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It makes perfect scents — why our dogs love to play with smelly rubbish

It makes perfect scents — why our dogs love to play with smelly rubbish
Nancy Dreschel
By Nancy Dreschel
14 Apr 2025
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It seems gross to us, but to our faithful friends our bins are a cornucopia of good scents and tasty treats – though some of it can cause harm.

When I think about why dogs do something, I try to imagine what motivates them. What does a dog get out of playing with trash? As a veterinarian and a professor who teaches college students about companion animals, I believe there’s an easy answer: garbage smells delicious and tastes good to dogs.

Dogs have an amazing sense of smell. They have 300 million receptors for smell in their noses, whereas humans have only six million. People can use this sniffing ability to train dogs to detect illegal drugs, explosives and endangered species, and to help locate people lost in the woods.

Although you might not like how your trash smells, to your dog it is an appealing buffet brimming with apple cores, banana peels, meat scraps and stale bread. Even used napkins and paper towels are tempting to dogs when they are smeared with and carry the smell of yesterday’s lunch.

Because dogs can find minuscule trace amounts of explosives or a person buried under 1.8m of snow after an avalanche, they are certainly capable of locating last night’s pizza crust and chicken bones in the kitchen rubbish bin.

Sometimes it’s hard to see what the attraction is. My Australian cattle dog mix, Sparky, loves to eat used tissues – gross, right?

Even empty cans smell inviting to dogs. Trash cans in kitchens and bathrooms are often at their nose level, too, making for easy access. Add to that the fact that if the dog got into the garbage once and found something tasty, they will probably keep searching with the hope of being rewarded again.

Thrill of the hunt


Searching and digging around for food is natural for dogs because it provides some of the thrill of the hunt, even if they just ate and aren’t hungry.

The most successful prehistoric dogs ate the bones and scraps that humans left behind more than 10,000 years ago. Hanging around humans and their garbage was a way they could get plenty to eat. Even your beloved pup today has some of those searching instincts.

Although our trash has changed from the days of hunting and gathering, the discarded paper napkins, plastic wrappers and food scraps we throw away all still smell like food to dogs. And this scavenging behaviour is still hardwired in our pampered pets.

It may look to us like they’re playing, but our dogs’ sniffing out and tearing things up from the trash and tossing them around mimics what their ancestors did when they tugged on and tore up an animal carcass they had found.

Many people take advantage of this instinct and use “snuffle mats” – cloth or paper where food is hidden – or puzzle feeding toys to keep their pups’ minds active. Having to hunt for and find their food helps them to use their noses and sharpens their skills.

Annoying or even dangerous


Spreading trash all over the home may be natural for dogs, but cleaning it up is no fun for the people they live with. And if your dog pokes its nose in a garbage bin, it could be in danger.

Eating plastic bags, string, chicken bones, chemicals or rotten food can cause blockages, diarrhoea and poisoning. Commonly referred to as “garbage gut”, garbage poisoning can be life-threatening.

I’ve treated dogs that had cut their tongues and mouths on cans or broken glass. I once performed surgery to remove a mielie cob from the intestines of a dog that had eaten it a month earlier. He was certainly relieved when he woke up.

Keeping dogs away from the trash


It can be hard to train a dog to leave garbage alone, especially if they have found a tasty morsel or two by raiding the trash can in the past. I recommend that you invest in a garbage can with a lid closed by a latch that they can’t open. If that fails, you can put garbage – especially food scraps – out of reach in a cupboard or behind a firmly closed door.

My trash cans are all behind closed doors, and the bathroom doors are always shut, which also keeps my cat, Penny, from unrolling the toilet tissue. But that’s another story. Our kitchen trash is in a latched cupboard.

No one knows exactly what goes through dogs’ minds. Yet looking at what motivates your canine companion and how dog behaviours have evolved may help to explain why these animals do the things they do. DM

First published by The Conversation.

Nancy Dreschel is an associate teaching professor of small animal science at Penn State University in Pennsylvania.

This story first appeared in our weekly Daily Maverick 168 newspaper, which is available countrywide for R35.

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